National Weather Service United States Department of Commerce

Storm Moving through the South; Pacific Storm to Impact the West this Weekend

A storm is expected to develop over the southern High Plains today and track to the Mid-Atlantic through Friday with showers and thunderstorms. On the northern edge, snow, ice, and/or a wintry mix is possible over the central Plains. A significant storm is expected to arrive late Friday through the weekend with rain, heavy mountain snow, and gusty winds for much of the West. Read More >

Late season severe squall line hammers the area

 

Synoptic conditions on November 06, 2005...
An intense mid level shortwave rapidly sharpened and took on a negative tilt as it progressed through the Great Lakes. A strong mid level jet of 80 to 90 knots at 500mb developed along the southern periphery of the digging shortwave and contributed to strong deep layer shear. Meanwhile a surface low pressure in the central plains moved northeast along a stationary front and quickly deepened in response to the sharpening mid level shortwave. The rapidly deepening low passed by just to the northwest of the CWA. The rapid deepening aided in keeping the surface flow backed (S or SSE). Strong deep layer shear and impressive low level helicity values (0-1km Helicity 300-400) were able to compensate for minimal CAPE values of 100-500J/kg.

Mesoscale/Stormscale conditions...
A cluster of supercells formed during the evening over Missouri and evolved into a squall line and crossed Illinois as linear forcing strengthened. The line initially weakened due to minimal instability as it entered into the CWA. Some strengthening occured as the line was about 1/3 through the CWA as synoptic scale forcing peaked. The line moved rapidly east through the eastern half of the CWA. Very strong mid level flow contributed to damaging wind potential at the surface. Despite very high values of 0-1km Helicity, tornadoes did not occur this far north, most likely due to a lack of boundary layer instability.

Radar trends and observations...
The squall line was very low topped by the time it reached Indiana, with echo tops of only 10-15 thousand feet. The squall line was broken into small scale segments (which were more perpindicular to the mid level flow) which locally enhanced wind damage. Low level mesocyclones along the leading edge of the squall line also aided in enhancing wind damage in some locations. Forward motion of the line was exceedingly fast, estimated at 70 to 75 mph.

Significant damage...
Grant county - Marion and Upland townships. 10 barns and 3 mobile homes destroyed. Dekalb county - Auburn. 4 homes suffered extensive damage. Paulding county - near Paulding. Several large oak trees blown down with damage to several homes

Widespread reports of of trees and powerlines down were recieved throughout Indiana...mainly east of Indiana Route 25 and south of U.S. Route 30. There were also numerous reports of structural damage to many barns and some homes damaged in areas of east central Indiana south of Fort Wayne. Widspread damage of a similar nature was also reported in much of northwest Ohio. All of the damage reported was consistent with that of strong straight line winds, and no tornadoes were reported in this area.


Click for a summary of wind damage reports

J.Hitchcock